Conventional junction field effect transistors (JFETs) are known. FIG. 19 shows a schematic diagram of a conventional n-channel JFET 1900. Conventional n-channel JFET operates as a three terminal device, including a control gate 1910, drain 1920, and source 1930. In operation, conventional JFET 1900 functions as a depletion mode device, providing a relatively low impedance path between source 1930 and drain 1920. In response to a voltage applied at control gate 1910, a depletion region can be altered to change the conductivity between source 1930 and drain 1920.
Currently, for most large scale integrated circuits, metal-oxide-semiconductor (MOS) type transistors are employed, due to perceived advantages over other transistor types, such as JFETs. Presently, most integrated circuits having logic functions are fabricated with complementary MOSFETs (CMOS) technology. CMOS employs both p-type MOSFETs and n-type MOSFETs. By doing so, at least one type of MOSFETs can be turned off in a steady state condition. In this way, steady state current may be reduced to transistor leakage current.
CMOS technology has long provided advantageous current leakage characteristics. However, as device feature sizes decrease, CMOS technology is approaching scaling limits. For example, as channel lengths of CMOS transistors decrease, a gate insulating layer thickness must be decreased in order to provide adequate control over the channel (and hence sufficiently turn the device off). Such thin gate insulating layers can become difficult or expensive to manufacture and/or lose integrity in operation or over time.